By using $4 6pS3 Russian tubes in place of $12 Svetlana or JJ 6L6 tubes we save $8 per tube or $32 off the price of a $500 amp. Less then 10% of the total.
Almost all the cost of an amp is the Iron and Chassis.
Even if 6L6 tubes were free you'd save only $48 which is still less than 10% of the total. The only way to get the cost way down, to say less then half is to have very sensitive speakers and then build a 10 or 12 watt amp that uses transformers that are half the size. The cost of the amp is directly proportional to the size of the transformers. The tubes hardly matter
Thanks for the info, Jeff.
Makes me wonder... I was looking at getting a good guaranteed frequency response off the tranny; The hammond goes up to 30Khz, while the normal human ear goes only up to maybe 20Khz. Some of the edcor ones only up to 18Khz, likely what my ears can perceive. If the vintage ones were not as great, would I be OK with something that covers only up to 10Khz?
I have found on the bay a ~20W PP output transformer that is intended for guitar amp and so have a frequency response up to 10Khz... see ebay item 160434574056 .
I guess after 10Khz it is somewhat distorded, suiting what older transformers would be able to achieve?
Would that be a good choice? seems like a good deal if it does what I want it to do...
Another question: is there a sound difference between vintage tubes and modern tubes, or is that only an urban legend? (maybe I should get a pair of modern 6V6 in my vintage amp and find out?)
Those output transformers with less bandwidth will roll off earlier and you might not notice or need the most high-end extension, but it's not just roll off that occurs. There is also some distortion (and you risk it greatly on the low end as deep bass can saturate the core and muddy the sound). Some people would say that you also miss the ultrasonics that, while we don't hear them directly, affect the timbre of cymbals and other instruments that resonate in that region.
Regarding vintage NOS (New Old Stock) and new tubes, you're entering a whole world of opinion. Many would say that you can't beat certain older production tubes, and yet as many would say that some of the newer SED, Sovtek, Genalex and Tung-Sol re-issues are truly excellent. The difference in sound among brands of a type is not only between old and new, but often between brands (or rather factories and manufacturing runs, since many brands are relabels of other brands and makers).
I would suggest that you settle on the topology and circuit type, determine the tube complement you need, do a little research on what people think of various 6V6s, get the tubes and output transformers and go from there. Those will help determine the power transformer, the design of the supply and some of other components.
Using guitar output transformers isn't all that bad an idea if you are on a tight budget and can operate them within good parameters. I used a Fender replacement 6.6KOhm OPT with 12AQ5s for a while before switching to a DynaClone Z-565. The switch was worth it, but the Fenders were okay enough to get me started. I think now I'd recommend Edcors for best bang you get for the price.
By the way, there are some good amp designs that use tubes in the 6V6 "family," the 6AQ5/6005/12AQ5 being one type. Output power differs some, but overall it's a broad family worth investigating, since the tube costs can vary and there are some good types that are still not too expensive. NOS 6V6s are getting more expensive, but you can still find others in that family at good prices. If you like octals, keep playing with the 6V6s, or go with what others have suggested.
I have enjoyed building the "El Cheapo" that Eli Duttman and Jim McShane designed. It uses 12AT7s and the 6- or 12AQ5s. A 6V6 will drop in well in place of the 12AQ5s without component changes (except for heater voltage and current), according to Eli. You'll see the Fender replacement (Triode Electronics) OPT spec'd on the schematic. You can find the plans for El Cheapo here (be prepared to wade through a lot of pages of excellent discussion):
Audiophiletalk - Bargain Basement
Post #683 (around page 57) has the latest schematic.
I would suggest going with a design that others have built or can recommend as a good design. Surely others will chime in here.
Hope this helps!
--Jeff
Regarding vintage NOS (New Old Stock) and new tubes, you're entering a whole world of opinion. Many would say that you can't beat certain older production tubes, and yet as many would say that some of the newer SED, Sovtek, Genalex and Tung-Sol re-issues are truly excellent. The difference in sound among brands of a type is not only between old and new, but often between brands (or rather factories and manufacturing runs, since many brands are relabels of other brands and makers).
I would suggest that you settle on the topology and circuit type, determine the tube complement you need, do a little research on what people think of various 6V6s, get the tubes and output transformers and go from there. Those will help determine the power transformer, the design of the supply and some of other components.
Using guitar output transformers isn't all that bad an idea if you are on a tight budget and can operate them within good parameters. I used a Fender replacement 6.6KOhm OPT with 12AQ5s for a while before switching to a DynaClone Z-565. The switch was worth it, but the Fenders were okay enough to get me started. I think now I'd recommend Edcors for best bang you get for the price.
By the way, there are some good amp designs that use tubes in the 6V6 "family," the 6AQ5/6005/12AQ5 being one type. Output power differs some, but overall it's a broad family worth investigating, since the tube costs can vary and there are some good types that are still not too expensive. NOS 6V6s are getting more expensive, but you can still find others in that family at good prices. If you like octals, keep playing with the 6V6s, or go with what others have suggested.
I have enjoyed building the "El Cheapo" that Eli Duttman and Jim McShane designed. It uses 12AT7s and the 6- or 12AQ5s. A 6V6 will drop in well in place of the 12AQ5s without component changes (except for heater voltage and current), according to Eli. You'll see the Fender replacement (Triode Electronics) OPT spec'd on the schematic. You can find the plans for El Cheapo here (be prepared to wade through a lot of pages of excellent discussion):
Audiophiletalk - Bargain Basement
Post #683 (around page 57) has the latest schematic.
I would suggest going with a design that others have built or can recommend as a good design. Surely others will chime in here.
Hope this helps!
--Jeff
Hello,
These Edcor transformers have a lot of bang for the buck.
EDCOR Electronics Corporation. CXPP25-4-7.6K
Only 3 weeks from July 4th order to my door. The output pair is going to be NOS WWII JAN 1625’s. The inputs and drivers will be 12SN7’s. The rectifiers will be 5AR4’s, one per side.
For what if and understanding Push Pull better take a look at this software.
TCJ Push-Pull Calculator - Download
DT
All just for fun!
These Edcor transformers have a lot of bang for the buck.
EDCOR Electronics Corporation. CXPP25-4-7.6K
Only 3 weeks from July 4th order to my door. The output pair is going to be NOS WWII JAN 1625’s. The inputs and drivers will be 12SN7’s. The rectifiers will be 5AR4’s, one per side.
For what if and understanding Push Pull better take a look at this software.
TCJ Push-Pull Calculator - Download
DT
All just for fun!
Jeff, do you think I could go with those transformers from the thread you're talking about:
TF110-48 UL Deluxe Style Ultra-Linear Output Transformer 4 / 8 ohm (Plastic Bobbin) for Fender 041318 MADE IN USA
and use it on that schematics (that I have read a lot of good online)
DIY Push-Pull (PP) 6V6 / 6V6GT Tube Amplifier Schematic
I am trying to get a similar sound to what I have in my vintage radio; I am under the impression that I wouldn't get this sound with "the best of the best" output transformer so rounding to a "lesser quality but fits the deal" could be closer to the quality they had back in the 40s. (might be a wrong assumption)
From what I have read online about the replacement part for the output transformer for my radio, it seems to have a its primary at 9000 ohm; would that influence sound output at all?
I didn't know audiophiletalk, thanks for the link. There's lots to read in that thread, with lots to learn from.
TF110-48 UL Deluxe Style Ultra-Linear Output Transformer 4 / 8 ohm (Plastic Bobbin) for Fender 041318 MADE IN USA
and use it on that schematics (that I have read a lot of good online)
DIY Push-Pull (PP) 6V6 / 6V6GT Tube Amplifier Schematic
I am trying to get a similar sound to what I have in my vintage radio; I am under the impression that I wouldn't get this sound with "the best of the best" output transformer so rounding to a "lesser quality but fits the deal" could be closer to the quality they had back in the 40s. (might be a wrong assumption)
From what I have read online about the replacement part for the output transformer for my radio, it seems to have a its primary at 9000 ohm; would that influence sound output at all?
I didn't know audiophiletalk, thanks for the link. There's lots to read in that thread, with lots to learn from.
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Russ, that's a cool idea. But I don't really want to take it off the chassis... I am affraid I could damage some wiring if I play with it; its older than my mother!!! Plus I have nothing to weight it (I know it sounds lame, but I really would prefer not moving it out of the chassis if not required)
It is rather small. Actually fits inside the chassis, sideways in the underside.
I'd say without dismounting the radio for measurments, about 2"x1.5"x1.5" - the ones I've seen online all seems bigger than the radio's.
I have read online that it was rated by philco (who made the radio) as:
Primary impedance: 9000
Secondary impedance: 3.5
power: 15W
(strange: the radio amp was rated at 10W)
Altough I want 8 ohm for the speakers so that will change things. The original radio's loudspeaker didn't have a permanent magnet. I don't really want to have high voltage trough my speakers so I won't be making the same speaker setup for sure.
It is rather small. Actually fits inside the chassis, sideways in the underside.
I'd say without dismounting the radio for measurments, about 2"x1.5"x1.5" - the ones I've seen online all seems bigger than the radio's.
I have read online that it was rated by philco (who made the radio) as:
Primary impedance: 9000
Secondary impedance: 3.5
power: 15W
(strange: the radio amp was rated at 10W)
Altough I want 8 ohm for the speakers so that will change things. The original radio's loudspeaker didn't have a permanent magnet. I don't really want to have high voltage trough my speakers so I won't be making the same speaker setup for sure.
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8K-10K is generally used with 6V6 - 9K is right in the middle... it's not critical.
The "el cheapo" uses triode mode, which simplifies things a LOT - low distortion, low output impedance with a simple circuit. But it will only make 4 watts or so - that may be enough for you. With pentode mode, some negative feedback is generally used to lower distortion and output impedance. And that calls for a better transformer, as does the higher power that you'll get.
The "el cheapo" uses triode mode, which simplifies things a LOT - low distortion, low output impedance with a simple circuit. But it will only make 4 watts or so - that may be enough for you. With pentode mode, some negative feedback is generally used to lower distortion and output impedance. And that calls for a better transformer, as does the higher power that you'll get.
So the 20W transformer mentionned in that article
TF110-48 UL Deluxe Style Ultra-Linear Output Transformer 4 / 8 ohm (Plastic Bobbin) for Fender 041318 MADE IN USA
wouldn't be good ennough for pentode mode?
I'd want to go in the 10W range, pentode mode...
TF110-48 UL Deluxe Style Ultra-Linear Output Transformer 4 / 8 ohm (Plastic Bobbin) for Fender 041318 MADE IN USA
wouldn't be good ennough for pentode mode?
I'd want to go in the 10W range, pentode mode...
Having used the TF110-48 UL in both triode and UL mode (not quite pentode mode, but sort of inbetween triode and pentode), I think they will do okay. The thing is, at $30 each, you're already on your way to a good pair of 15 Watt Edcors, and if you go with the G series, rather than the cheaper X series, you'll have better bass extension and a little more headroom. I've talked with Edcor about the differences, and they confirmed that the G series offers better low end extension. You won't be disappointed with the X series if you need to stay in a tight budget. Be sure, however, that the PP Edcor OPTs offer the UL taps you'd need.
The edcor that seems to make more sense would be the GXPP15-8-8K
EDCOR Electronics Corporation. GXPP15-8-8K
You are right, Jeff, the little price difference might not be worth the output difference. Plus, I will likely get the power transformer at the same time and save on shipping.
My main question remains; would a "lower bandwidth transformer" give results more similar to older ones? or should I not care about that and go straight ahead with better ones?
EDCOR Electronics Corporation. GXPP15-8-8K
You are right, Jeff, the little price difference might not be worth the output difference. Plus, I will likely get the power transformer at the same time and save on shipping.
My main question remains; would a "lower bandwidth transformer" give results more similar to older ones? or should I not care about that and go straight ahead with better ones?
I'm repeating what has already been said here.
Recreating the sound of your older radio (small OPT and probably leaky capacitors as well) will be difficult.
Anything you build will probably be more 'hi-fi' (accurate, better bandwidth) than your radio.
If you are not on a tight budget, or in a hurry I would advise going for the Edcors - they are good for delivery in Canada. BTW, Matt at eBay - the seller whose auction you linked- is a reliable guy to deal with. If you go directly to his website musicalpowersupplies.com you will find that the prices are a bit lower than at eBay. Also, he is good to ship to Canada using USPS flat rate boxes. I've built a few hifi projects with his OTs, but the better Edcor stuff is heavier and should perform better, at a higher price.
Since guitar amps are mono, few of the guitar power transformers can deliver the current you need for a stereo project. So you will probably need to go to Edcor anyway for the PT; might as well buy the OT from them as well.
re:Hammond- I haven't found anywhere in Canada to buy Hammond iron at a good price. Another possibility for PT and chokes is Allied - they ship from a Canadian location and the Allied brand PTs and Triad chokes are cheap.
You won't have any trouble getting parts sent to you in Canada- I should know; I've got a pile of parts here!
Send me a pm and I can email you a list of suppliers I have here somewhere.
About OTs and bandwidth - I'd concentrate on the bass response figures as well as the high end.
Cheers
John
+1 and I'll add some more...
That's odd. Hammond is a Canadian company and makes most of the transformers in Canada. Having them shipped from the US seems silly. But if you must buy them in the US I think STF Electronics always has the best price on Hammond with free shipping in the US only.
Hammond is first rate but also check of the "clasic tone" brand sold buy Triode Electronics. Prices are good and the selection is better than what's offered at Musical Power Supply. Magnetic Components, the company who makes there uses the old 1950's vintage methods, paper insulation and so on. Their intent is to duplicate the old sound. If that is your goal look into this brand.
To answer the quetion "will it sound like my old radio? Well you can get close. The sound is determined by in order of importance: (1) the speaker. this is by far the most importance, swamping everything else combined. (2) the output transformer and (3) the type of tubes that is 6v6 or El84 or whatever, not the brand of tube. Do not expect an exact match to the sound you want on the first try. Amps ALWAYS need to be "tweaked". Likley ned to play with the amount of global negative feedback and the size of a few coupling caps and maybe the compensation cpas in the feedback network.
An old radio is likely pretty lo-hi and you'd be fine to use guitar amp parts to recreate the effect. I would not use a guitar speaker, those are very specialized with narrow frequency response to only cover the range of a guitar (about 80Hz to 5K) and they typically have the mids cut. Exactly 'wrong" for playing recorded music. Perfect for producing music, just not re-producing it.
But there are any number of inexpensive paper code speakers at Parts Express and they have good technical data on everything they sell.
To get a good match up you will need to measure the parts you have now. without real measured data we are all just guessing.
John, I agree on the output transformer, but there's not any leaky capacitors left on the amp, as they were changed to modern equivalent by yours truly.
If the speaker is more important than the output transformer to recreate a sound, would it mean I need to go with a field coil speaker?? I have similar size speaker I was hoping to use.
I guess I'll be going the route of Edcor, unless their shipping is outreagous. I'll need a power transformer and might want to order all of them at once.
Let say I want to use 6V6s and GXPP15-8-8K on each channels...
what next? do I choose the power transformer then? (and how?)
If the speaker is more important than the output transformer to recreate a sound, would it mean I need to go with a field coil speaker?? I have similar size speaker I was hoping to use.
I guess I'll be going the route of Edcor, unless their shipping is outreagous. I'll need a power transformer and might want to order all of them at once.
Let say I want to use 6V6s and GXPP15-8-8K on each channels...
what next? do I choose the power transformer then? (and how?)
Tek: Good!
No need to go with a field coil speaker, IMO. Are you planning to use a single speaker for each channel, or crossover with 2-3 drivers/channel?
Speakers pulled from a stereo tube console might do the trick. Msg me if you are interested in 3-way from a stereo console.
Organ speakers would be another option, but it's often tough to find pairs.
You'll probably have to do some experimenting. I agree with ChrisA that speakers have more influence on the sound than any other individual factor - by a big amount.
Well, postage is expensive, and there is extra paperwork to send stuff across the border. I got a box with 4 transformers from Edcor the other day - shipping was around $45- plenty, but not outrageous. Insist on USPS, NOT FedEx/UPS, and try to get them to ship in a flat rate box - 20 lbs for ~$34?
Have you decided to use this schematic?:
DIY Push-Pull (PP) 6V6 / 6V6GT Tube Amplifier Schematic
It specs Hammond iron (8k UL OTs and 300-0-300 200mA power) which you can get from AntiqueElectronicSupply aka AES aka tubesandmore.com.
(I have dealt with them cross border.) About $200 US for the three transformers. Shop around and check out other sources; there may be better prices out there.
Or have you decided on something pentode mode (eg wiring that schematic in pentode instead of UL)? It's easy to experiment with UL if your OT has UL taps, but there are more OTs available to choose from if you don't need the UL tap.
John
John, my current idea is to use those schematics, but to adapt to the transformers I would be choosing. Although I am uncertain how to adapt the schematics...
For speakers, I currently have a pair of 3-way "columns" from an 80's SS stereo system; they sounded OK on 80's tech. Once the amp is done, I might want to change but for now they should be a good start.
On another note, I received my lot of octal sockets. If I choose only octal tubes, I already have all the bases I need.
For speakers, I currently have a pair of 3-way "columns" from an 80's SS stereo system; they sounded OK on 80's tech. Once the amp is done, I might want to change but for now they should be a good start.
On another note, I received my lot of octal sockets. If I choose only octal tubes, I already have all the bases I need.
If you are going to build that schematic (modified Dynaco?) then the easiest thing would be to use the same transformers, if the cost isn't a big problem- since they are current production items.
Do you have a preamp?
What audio/music source are you going to use for your project? (CD/DAC or Phono?)
John
Hello,
I did some shopping for the Hammond 272HX power transformer. I ended up buying from Gerber Electronics - Browse Parts - Our Greatest Component is Your Satisfaction . They supplied the current 230ma version, the one with 115 volt and 125 volt taps on the primary. I had never heard of Gerber before, they had about the best price. The service was fast and good.
The Edcor output transformers are less than half the price of the Hammond 1608A transformers.
All just for fun!
I did some shopping for the Hammond 272HX power transformer. I ended up buying from Gerber Electronics - Browse Parts - Our Greatest Component is Your Satisfaction . They supplied the current 230ma version, the one with 115 volt and 125 volt taps on the primary. I had never heard of Gerber before, they had about the best price. The service was fast and good.
The Edcor output transformers are less than half the price of the Hammond 1608A transformers.
All just for fun!
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John, if I wanted to blindly follow a schematics and not learn anything, then I wouldn't have started this thread.
I agree, it isn't the easiest thing to do, but I want to learn out of doing an amp and select the components, not simply blindly follow a pre-designed amp one... I could blindly follow a design, I could also buy a pre-made kit or get a commercial amp. Where's the fun?
I don't currently have a pre-amp, do I really need one? I plan on using this amp for CD/Mp3 computer/DVD/Videogame consoles. As far as I know, all line-level output.
I agree, it isn't the easiest thing to do, but I want to learn out of doing an amp and select the components, not simply blindly follow a pre-designed amp one... I could blindly follow a design, I could also buy a pre-made kit or get a commercial amp. Where's the fun?
I don't currently have a pre-amp, do I really need one? I plan on using this amp for CD/Mp3 computer/DVD/Videogame consoles. As far as I know, all line-level output.
If you want Output transformers with UL taps you are best to go with around 25% UL as discussed in various forms. Nice option to have in your investment.
Edcor make one
EDCOR Electronics Corporation. CXPP25-MS-8K/23%
and the Dynaclone Z-565 from Triode Electronics or Dynakit.com have them.
If 25 % UL isn't as important look at this one as it has a 8.6K input better for 6V6 types.
EDCOR Electronics Corporation. CXPP21-MS-8.6K
Eric Kingsberry or the "Poinz" with his 6V6 Musical Machine recommended actually 10-12K and so mentioned the Silk P-10-15A.
In testing the Z-565 on AudioKarma and diytube forms by a member it was found you could get 20-20KHZ at full rated power with really low distortion. As mentioned you will get less distortion, so it might be best to stick to this quality of an Output transformer which is proven. Don't know how the Edcors compare. You sure notice the difference between output transformers. Even with a lower bandwidth input it's readily apparent so buy the best you can afford.
Here's an interesting circuit which I think might be worth looking at, as it is similar to what your looking at but may be an improvement. Read about the changes to the coupling caps in the end. You could use a good choke PS like mentions from another small amp.
Magnavox Paraphase 15 wpc P-P Amplifier
Edcor make one
EDCOR Electronics Corporation. CXPP25-MS-8K/23%
and the Dynaclone Z-565 from Triode Electronics or Dynakit.com have them.
If 25 % UL isn't as important look at this one as it has a 8.6K input better for 6V6 types.
EDCOR Electronics Corporation. CXPP21-MS-8.6K
Eric Kingsberry or the "Poinz" with his 6V6 Musical Machine recommended actually 10-12K and so mentioned the Silk P-10-15A.
In testing the Z-565 on AudioKarma and diytube forms by a member it was found you could get 20-20KHZ at full rated power with really low distortion. As mentioned you will get less distortion, so it might be best to stick to this quality of an Output transformer which is proven. Don't know how the Edcors compare. You sure notice the difference between output transformers. Even with a lower bandwidth input it's readily apparent so buy the best you can afford.
Here's an interesting circuit which I think might be worth looking at, as it is similar to what your looking at but may be an improvement. Read about the changes to the coupling caps in the end. You could use a good choke PS like mentions from another small amp.
Magnavox Paraphase 15 wpc P-P Amplifier
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